This invention relates to valves for use with or for incorporation with liner bags as used in containers to house liquids. In the following description the term liquids is to be understood to mean materials which have a viscosity, either inherent or induced by heat or other means, which allows the material to flow under the influence of gravity. At the ends of the range of materials contemplated would be water and a material, such as lard, which is solid in its natural condition at room temperature, but when heated can flow and gravity discharge from a container.
It is common practice to store and transport liquids in containers which include a base (conventionally adapted to act as a pallet with means to allow the use of a fork lift truck or a hand truck), four sides coupled to the base and a lid. A plastic film liner bag is located in the container to house the liquid. Discharge of the liquid is achieved through a nozzle mounted on the bag and accessible from outside the container.
In order to discharge the contents of the container several strategies have been developed. In one, a bottom discharge arrangement, the liner bag nozzle is in direct communication with the interior of the liner bag. The nozzle extends down into the base and then outwardly towards a side of the base. There is a manually operable butterfly or like valve in the nozzle to control the discharge of the liquid from the liner bag. The nozzle at its outlet end is threaded allowing a delivery hose to be coupled to the nozzle after the removal of a sealing cap, normally resident on the thread. The cap protects the nozzle thread against damage and prevents contamination entering the nozzle. The cap also serves a third and most important double security purpose. It ensures that any leakage through the butterfly valve when closed is contained in the nozzle and the cap usually has an associated tamper detection means. The liner bag and its butterfly valved nozzle is a one-use only item.
A bottom discharge liner bag with an integral nozzle with valve, as just described, is far more expensive than a liner bag with a nozzle for side discharge, another strategy in use for discharging liquid from containers. In the side discharge arrangement the nozzle has no valve. The nozzle is threaded at its outlet end for a cap. Because the nozzle bore is not in direct communication with the interior of the liner bag, being separated from the liner bag contents by a membrane over the inlet end of the bore of the nozzle, the cap does not need to be a sealing cap or include a tamper detection means. A one-use liner bag for side discharge is thus considerably cheaper than the one-use liner bag for a bottom discharge system. Cost is an important factor when the liner bag is used only once and then discarded.
In the side discharge arrangement the capped nozzle discharge end projects from a side of the container. In a discharge operation, the cap is removed and a membrane rupturing device is inserted into the nozzle. The rupturing device is forced against the membrane as a reusable valve is threaded onto the nozzle. It follows that as soon as the membrane is ruptured the liner bag contents will enter the nozzle but discharge from the nozzle is prevented by the coupled reusable valve until discharge of the liner bag contents is required.
Whilst the side discharge system has several economic and practical advantages over the bottom discharge system there has been a perceived need for a system which has the good features of both systems. The bottom discharge system has the advantage that the valve is part of the bag nozzle and is discarded with the bag, but the disadvantage that the membrane concept of the side discharge system cannot be utilized with known nozzle/valve assemblies.
The present invention has been devised to provide a valve assembly for use with or incorporation with container liner bags, where the valve means acts as a discharge nozzle and is a self contained inexpensive disposable unit which incorporates a membrane puncturing arrangement.
Broadly stated the invention provides a valve assembly including a body with a through bore having an inlet end and a discharge end, flange means on the body around and adjacent the inlet end of the body bore whereby the valve means can be secured to the wall of a liner bag for a container, a closure member movable along the body bore between a closed condition in which sealing means on the closure member and the body bore engage to isolate the inlet end of the body bore from the discharge end of the body bore and an open condition in which said sealing means are separated to place the body bore inlet and discharge ends in communication, membrane puncturing means on the closure member upstream from the sealing means on the closure member and manually operable closure member moving means whereby said closure member can be moved between said closed condition in which said membrane puncturing means lies within said body bore and a fully open condition in which said membrane puncturing means projects beyond the inlet end of the body bore.